Molecular sieve compositions, catalyst thereof, their making and use in conversion processes

ABSTRACT

The invention relates to a catalyst composition, a method of making the same and its use in the conversion of a feedstock, preferably an oxygenated feedstock, into one or more olefin(s), preferably ethylene and/or propylene. The catalyst composition comprises a molecular sieve and at least one oxide of a metal from Group 4, optionally in combination with at least one metal from Groups 2 and 3, of the Periodic Table of Elements.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 120 from U.S.Provisional Patent Application Ser. No. 60/360,963 filed Feb. 28, 2002and from U.S. Provisional Patent Application Ser. No. 60/366,012 filedMar. 20, 2002, the entire contents of which applications areincorporated herein by reference.

FIELD

The present invention relates to molecular sieve compositions andcatalysts containing the same, to the synthesis of such compositions andcatalysts and to the use of such compositions and catalysts inconversion processes to produce olefin(s).

BACKGROUND

Olefins are traditionally produced from petroleum feedstocks bycatalytic or steam cracking processes. These cracking processes,especially steam cracking, produce light olefin(s), such as ethyleneand/or propylene, from a variety of hydrocarbon feedstocks. Ethylene andpropylene are important commodity petrochemicals useful in a variety ofprocesses for making plastics and other chemical compounds.

The petrochemical industry has known for some time that oxygenates,especially alcohols, are convertible into light olefin(s). There arenumerous technologies available for producing oxygenates includingfermentation or reaction of synthesis gas derived from natural gas,petroleum liquids or carbonaceous materials including coal, recycledplastics, municipal waste or any other organic material. Generally, theproduction of synthesis gas involves a combustion reaction of naturalgas, mostly methane, and an oxygen source into hydrogen, carbon monoxideand/or carbon dioxide. Other known syngas production processes includeconventional steam reforming, autothermal reforming, or a combinationthereof.

Methanol, the preferred alcohol for light olefin production, istypically synthesized from the catalytic reaction of hydrogen, carbonmonoxide and/or carbon dioxide in a methanol reactor in the presence ofa heterogeneous catalyst. For example, in one synthesis process methanolis produced using a copper/zinc oxide catalyst in a water-cooled tubularmethanol reactor. The preferred process for converting a feedstockcontaining methanol into one or more olefin(s), primarily ethyleneand/or propylene, involves contacting the feedstock with a molecularsieve catalyst composition.

Molecular sieves are porous solids having pores of different sizes suchas zeolites or zeolite-type molecular sieves, carbons and oxides. Themost commercially useful molecular sieves for the petroleum andpetrochemical industries are known as zeolites, for examplealuminosilicate molecular sieves. Zeolites in general have a one-, two-or three-dimensional crystalline pore structure having uniformly sizedpores of molecular dimensions that selectively adsorb molecules that canenter the pores, and exclude those molecules that are too large.

There are many different types of molecular sieve well known to converta feedstock, especially an oxygenate containing feedstock, into one ormore olefin(s). For example, U.S. Pat. No. 5,367,100 describes the useof the zeolite, ZSM-5, to convert methanol into olefin(s); U.S. Pat. No.4,062,905 discusses the conversion of methanol and other oxygenates toethylene and propylene using crystalline aluminosilicate zeolites, forexample Zeolite T, ZK5, erionite and chabazite; U.S. Pat. No. 4,079,095describes the use of ZSM-34 to convert methanol to hydrocarbon productssuch as ethylene and propylene; and U.S. Pat. No. 4,310,440 describesproducing light olefin(s) from an alcohol using a crystallinealuminophosphate, often designated AlPO₄.

Some of the most useful molecular sieves for converting methanol toolefin(s) are silicoaluminophosphate molecular sieves.Silicoaluminophosphate (SAPO) molecular sieves contain athree-dimensional microporous crystalline framework structure of [SiO₄],[AlO₄] and [PO₄] corner sharing tetrahedral units. SAPO synthesis isdescribed in U.S. Pat. No. 4,440,871, which is herein fully incorporatedby reference. SAPO molecular sieves are generally synthesized by thehydrothermal crystallization of a reaction mixture of silicon-,aluminum- and phosphorus-sources and at least one templating agent.Synthesis of a SAPO molecular sieve, its formulation into a SAPOcatalyst, and its use in converting a hydrocarbon feedstock intoolefin(s), particularly where the feedstock is methanol, are disclosedin U.S. Pat. Nos. 4,499,327, 4,677,242, 4,677,243, 4,873,390, 5,095,163,5,714,662 and 6,166,282, all of which are herein fully incorporated byreference.

Typically, molecular sieves are formed into molecular sieve catalystcompositions to improve their durability in commercial conversionprocesses. These molecular sieve catalyst compositions are formed bycombining the molecular sieve and a matrix material usually in thepresence of a binder. The purpose of the binder is hold the matrixmaterial, often a clay, to the molecular sieve.

Although it is known to use binders and matrix materials to formmolecular sieve catalyst compositions useful in converting oxygenatesinto olefin(s), these binders and matrix materials typically only serveto provide desired physical characteristics to the catalyst composition,and have little to no effect on conversion and selectivity of themolecular sieve. It would therefore be desirable to have an improvedmolecular sieve catalyst composition having a better conversion rate,improved olefin selectivity and a longer lifetime.

U.S. Pat. No. 4,465,889 describes a catalyst composition comprising asilicalite molecular sieve impregnated with a thorium, zirconium, ortitanium metal oxide for use in converting methanol, dimethyl ether, ora mixture thereof into a hydrocarbon product rich in iso-C₄ compounds.

U.S. Pat. No. 6,180,828 discusses the use of a modified molecular sieveto produce methylamines from methanol and ammonia, where for example, asilicoaluminophosphate molecular sieve is combined with one or moremodifiers, such as a zirconium oxide, a titanium oxide, an yttriumoxide, montmorillonite or kaolinite.

U.S. Pat. No. 5,417,949 relates to a process for converting noxiousnitrogen oxides in an oxygen containing effluent into nitrogen and waterusing a molecular sieve and a metal oxide binder, where the preferredbinder is titania and the molecular sieve is an aluminosilicate.

EP-A-312981 discloses a process for cracking vanadium-containinghydrocarbon feed streams using a catalyst composition comprising aphysical mixture of a zeolite embedded in an inorganic refractory matrixmaterial and at least one oxide of beryllium, magnesium, calcium,strontium, barium or lanthanum, preferably magnesium oxide, on asilica-containing support material.

Kang and Inui, Effects of decrease in number of acid sites located onthe external surface of Ni-SAPO-34 crystalline catalyst by themechanochemical method, Catalysis Letters 53, pages 171-176 (1998)disclose that the shape selectivity can be enhanced and the cokeformation mitigated in the conversion of methanol to ethylene overNi-SAPO-34 by milling the catalyst with MgO, CaO, BaO or Cs₂O onmicrospherical non-porous silica, with BaO being the most preferred.

International Publication No. WO 98/29370 discloses the conversion ofoxygenates to olefins over a small pore non-zeolitic molecular sievecontaining a metal selected from the group consisting of a lanthanide,an actinide, scandium, yttrium, a Group 4 metal, a Group 5 metal orcombinations thereof.

SUMMARY

In one aspect, the invention resides in a catalyst compositioncomprising a molecular sieve and at least one oxide of a metal selectedfrom Group 4 of the Periodic Table of Elements, wherein said metal oxidehas an uptake of carbon dioxide at 100° C. of at least 0.03, andtypically at least 0.035, mg/m² of the metal oxide.

The catalyst composition may also include at least one of a binder and amatrix material different from said metal oxide.

The catalyst composition may also include an oxide of a metal selectedfrom Group 2 and Group 3 of the Periodic Table of Elements. In oneembodiment, the Group 4 metal oxide comprises zirconium oxide and theGroup 2 and/or Group 3 metal oxide comprises one or more oxides selectedfrom calcium oxide, barium oxide, lanthanum oxide, yttrium oxide andscandium oxide.

The molecular sieve conveniently comprises a framework including atleast two tetrahedral units selected from [SiO₄], [AlO₄] and [PO₄]units, such as a silicoaluminophosphate.

In another aspect, the invention resides in a molecular sieve catalystcomposition comprising an active Group 4 metal oxide and a Group 2and/or a Group 3 metal oxide, a binder, a matrix material, and asilicoaluminophosphate molecular sieve.

In another aspect, the invention resides in a method for making acatalyst composition, the method comprising the step of physicallymixing first particles comprising a molecular sieve with secondparticles comprising a Group 4 metal oxide having an uptake of carbondioxide at 100° C. of at least 0.03 mg/m² of the metal oxide particles.

In one embodiment, the molecular sieve, a binder and a matrix materialare made into a formulated molecular sieve catalyst composition that isthen contacted, mixed, combined, spray dried, or the like, with anactive Group 4 metal oxide, such as an active zirconium metal oxideand/or an active hafnium metal oxide, optionally in the presence of aGroup 2 and/or a Group 3 metal oxide.

In another aspect, the invention resides in a method of making acatalyst composition, the method comprising:

-   -   (i) synthesizing a molecular sieve from a reaction mixture        comprising at least one templating agent and at least two of a        silicon source, a phosphorus source and an aluminum source; and    -   (ii) recovering the molecular sieve synthesized in step (i);    -   (iii) forming a hydrated precursor to a Group 4 metal oxide by        precipitation from a solution containing a source of Group 4        metal metal ions;    -   (iv) recovering the hydrated precursor formed in step (iii);    -   (v) calcining the hydrated precursor recovered in step (iv) to        form a calcined metal oxide that has an uptake of carbon dioxide        at 100° C. of at least 0.03 mg/m² of the metal oxide; and    -   (vi) physically mixing the molecular sieve recovered in step (i)        and the calcined metal oxide of step (v).

In yet another aspect, the invention is directed to a process forproducing olefin(s) by converting a feedstock, such as an oxygenate,conveniently an alcohol, for example methanol, in the presence of any ofthe above molecular sieve compositions and/or molecular sieve orformulated molecular sieve catalyst compositions.

In yet another aspect, the invention is directed to a process forconverting a feedstock into one or more olefin(s) in the presence of amolecular sieve catalyst composition comprising a molecular sieve, abinder, a matrix material and a mixture of metal oxides different fromthe binder and the matrix material.

In one embodiment, the catalyst composition has a Lifetime EnhancementIndex (LEI) greater than 1, such as greater than 1.5. LEI is definedherein as the ratio of the lifetime of the catalyst composition to thatof the same catalyst composition in the absence of an active metaloxide.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Introduction

The invention is directed to a molecular sieve catalyst composition andto its use in the conversion of hydrocarbon feedstocks, particularlyoxygenated feedstocks, into olefin(s). It has been found that combininga molecular sieve with one or more active metal oxides results in acatalyst composition with an enhanced olefin yield and/or a longerlifetime when used in the conversion of feedstocks, such as oxygenates,more particularly methanol, into olefin(s). In addition, the resultantcatalyst composition tends to be more propylene selective and to yieldlower amounts of unwanted ethane and propane, together with otherundesirable compounds, such as aldehydes and ketones, specificallyacetaldehyde.

The preferred active metal oxides are those having a Group 4 metal (forexample zirconium and hafnium) from the Periodic Table of Elements usingthe IUPAC format described in the CRC Handbook of Chemistry and Physics,78th Edition, CRC Press, Boca Raton, Fla. (1997). In some cases, it isfound that improved results are obtained when the catalyst compositionalso contains at least one oxide of a metal selected from Group 2 and/orGroup 3 of the Periodic Table of Elements.

Molecular Sieves

Molecular sieves have been classified by the Structure Commission of theInternational Zeolite Association according to the rules of the IUPACCommission on Zeolite Nomenclature. According to this classification,framework-type zeolite and zeolite-type molecular sieves, for which astructure has been established, are assigned a three letter code and aredescribed in the Atlas of Zeolite Framework Types, 5th edition,Elsevier, London, England (2001), which is herein fully incorporated byreference.

Crystalline molecular sieves all have a 3-dimensional, four-connectedframework structure of corner-sharing [TO₄] tetrahedra, where T is anytetrahedrally coordinated cation. Molecular sieves are typicallydescribed in terms of the size of the ring that defines a pore, wherethe size is based on the number of T atoms in the ring. Otherframework-type characteristics include the arrangement of rings thatform a cage, and when present, the dimension of channels, and the spacesbetween the cages. See van Bekkum, et al., Introduction to ZeoliteScience and Practice, Second Completely Revised and Expanded Edition,Volume 137, pages 1-67, Elsevier Science, B.V., Amsterdam, Netherlands(2001).

Non-limiting examples of molecular sieves are the small pore molecularsieves, AEI, AFT, APC, ATN, ATT, ATV, AWW, BIK, CAS, CHA, CHI, DAC, DDR,EDI, ERI, GOO, KFI, LEV, LOV, LTA, MON, PAU, PHI, RHO, ROG, THO, andsubstituted forms thereof; the medium pore molecular sieves, AFO, AEL,EUO, HEU, FER, MEL, MFI, MTW, MTT, TON, and substituted forms thereof;and the large pore molecular sieves, EMT, FAU, and substituted formsthereof. Other molecular sieves include ANA, BEA, CFI, CLO, DON, GIS,LTL, MER, MOR, MWW and SOD. Non-limiting examples of preferred molecularsieves, particularly for converting an oxygenate containing feedstockinto olefin(s), include AEL, AFY, AEI, BEA, CHA, EDI, FAU, FER, GIS,LTA, LTL, MER, MFI, MOR, MTT, MWW, TAM and TON. In one preferredembodiment, the molecular sieve of the invention has an AEI topology ora CHA topology, or a combination thereof, most preferably a CHAtopology.

The small, medium and large pore molecular sieves have from a 4-ring toa 12-ring or greater framework-type. In a preferred embodiment, thezeolitic molecular sieves have 8-, 10- or 12-ring structures and anaverage pore size in the range of from about 3 Å to 15 Å. In a morepreferred embodiment, the molecular sieves, preferablysilicoaluminophosphate molecular sieves, have 8-rings and an averagepore size less than about 5 Å, such as in the range of from 3 Å to about5 Å, for example from 3 Å to about 4.5 Å, and particularly from 3.5 Å toabout 4.2 Å.

Molecular sieves have a molecular framework of one, preferably two ormore corner-sharing [TO₄] tetrahedral units, more preferably, two ormore [SiO₄], [AlO₄] and/or [PO₄] tetrahedral units, and most preferably[SiO₄], [AlO₄] and [PO₄] tetrahedral units. These silicon, aluminum, andphosphorus based molecular sieves and metal containing derivativesthereof have been described in detail in numerous publications includingfor example, U.S. Pat. No. 4,567,029 (MeAPO where Me is Mg, Mn, Zn, orCo), U.S. Pat. No. 4,440,871 (SAPO), European Patent Application EP-A-0159 624 (ELAPSO where El is As, Be, B, Cr, Co, Ga, Ge, Fe, Li, Mg, Mn,Ti or Zn), U.S. Pat. No. 4,554,143 (FeAPO), U.S. Pat. Nos. 4,822,478,4,683,217, 4,744,885 (FeAPSO), EP-A-0 158 975 and U.S. Pat. No.4,935,216 (ZnAPSO, EP-A-0 161 489 (CoAPSO), EP-A-0 158 976 (ELAPO, whereEL is Co, Fe, Mg, Mn, Ti or Zn), U.S. Pat. No. 4,310,440 (AlPO₄), EP-A-0158 350 (SENAPSO), U.S. Pat. No. 4,973,460 (LiAPSO), U.S. Pat. No.4,789,535 (LiAPO), U.S. Pat. No. 4,992,250 (GeAPSO), U.S. Pat. No.4,888,167 (GeAPO), U.S. Pat. No. 5,057,295 (BAPSO), U.S. Pat. No.4,738,837 (CrAPSO), U.S. Pat. Nos. 4,759,919, and 4,851,106 (CrAPO),U.S. Pat. Nos. 4,758,419, 4,882,038, 5,434,326 and 5,478,787 (MgAPSO),U.S. Pat. No. 4,554,143 (FeAPO), U.S. Pat. No. 4,894,213 (AsAPSO), U.S.Pat. No. 4,913,888 (AsAPO), U.S. Pat. Nos. 4,686,092, 4,846,956 and4,793,833 (MnAPSO), U.S. Pat. Nos. 5,345,011 and 6,156,931 (MnAPO), U.S.Pat. No. 4,737,353 (BeAPSO), U.S. Pat. No. 4,940,570 (BeAPO), U.S. Pat.Nos. 4,801,309, 4,684,617 and 4,880,520 (TiAPSO), U.S. Pat. Nos.4,500,651, 4,551,236 and 4,605,492 (TiAPO), U.S. Pat. Nos. 4,824,554,4,744,970 (CoAPSO), U.S. Pat. No. 4,735,806 (GaAPSO) EP-A-0 293 937(QAPSO, where Q is framework oxide unit [QO₂]), as well as U.S. Pat.Nos. 4,567,029, 4,686,093, 4,781,814, 4,793,984, 4,801,364, 4,853,197,4,917,876, 4,952,384, 4,956,164, 4,956,165, 4,973,785, 5,241,093,5,493,066 and 5,675,050, all of which are herein fully incorporated byreference.

Other molecular sieves include those described in R. Szostak, Handbookof Molecular Sieves, Van Nostrand Reinhold, New York, N.Y. (1992), whichis herein fully incorporated by reference.

The more preferred molecular sieves include aluminophosphate (AlPO)molecular sieves and silicoaluminophosphate (SAPO) molecular sieves andsubstituted, preferably metal substituted, AlPO and SAPO molecularsieves. The most preferred molecular sieves are SAPO molecular sieves,and metal substituted SAPO molecular sieves. In an embodiment, the metalis an alkali metal of Group 1 of the Periodic Table of Elements, analkaline earth metal of Group 2 of the Periodic Table of Elements, arare earth metal of Group 3 of the Periodic Table of Elements, includingthe Lanthanides: lanthanum, cerium, praseodymium, neodymium, samarium,europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium,ytterbium and lutetium; and scandium or yttrium, a transition metal ofGroups 4 to 12 of the Periodic Table of Elements, or mixtures of any ofthese metal species. In one preferred embodiment, the metal is selectedfrom the group consisting of Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni, Sn, Ti,Zn and Zr, and mixtures thereof. In another preferred embodiment, thesemetal atoms discussed above are inserted into the framework of amolecular sieve through a tetrahedral unit, such as [MeO₂], and carry anet charge depending on the valence state of the metal substituent. Forexample, in one embodiment, when the metal substituent has a valencestate of +2, +3, +4, +5, or +6, the net charge of the tetrahedral unitis between −2 and +2.

In one embodiment, the molecular sieve, as described in many of the U.S.patents mentioned above, is represented by the empirical formula, on ananhydrous basis:mR:(M_(x)Al_(y)P_(z))O₂wherein R represents at least one templating agent, preferably anorganic templating agent; m is the number of moles of R per mole of(M_(x)Al_(y)P_(z))O₂ and has a value from 0 to 1, preferably 0 to 0.5,and most preferably from 0 to 0.3; x, y, and z represent the molefraction of Al, P and M as tetrahedral oxides, where M is a metalselected from one of Groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14 and Lanthanide's of the Periodic Table of Elements, preferably M isselected from one of the group consisting of Si, Co, Cr, Cu, Fe, Ga, Ge,Mg, Mn, Ni, Sn, Ti, Zn and Zr. In an embodiment, m is greater than orequal to 0.2, and x, y and z are greater than or equal to 0.01. Inanother embodiment, m is greater than 0.1 to about 1, x is greater than0 to about 0.25, y is in the range of from 0.4 to 0.5, and z is in therange of from 0.25 to 0.5, more preferably m is from 0.15 to 0.7, x isfrom 0.01 to 0.2, y is from 0.4 to 0.5, and z is from 0.3 to 0.5.

Non-limiting examples of SAPO and AlPO molecular sieves useful hereininclude one or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16,SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,SAPO-40, SAPO-41, SAPO-42, SAPO-44 (U.S. Pat. No. 6,162,415), SAPO-47,SAPO-56, AlPO-5, AlPO-11, AlPO-18, AlPO-31, AlPO-34, AlPO-36, AlPO-37,AlPO-46, and metal containing molecular sieves thereof. Of these,particularly useful molecular sieves are one or a combination ofSAPO-18, SAPO-34, SAPO-35, SAPO-44, SAPO-56, AlPO-18 and AlPO-34 andmetal containing derivatives thereof, such as one or a combination ofSAPO-18, SAPO-34, AlPO-34 and AlPO-18, and metal containing derivativesthereof, and especially one or a combination of SAPO-34 and AlPO-18, andmetal containing derivatives thereof.

In an embodiment, the molecular sieve is an intergrowth material havingtwo or more distinct crystalline phases within one molecular sievecomposition. In particular, intergrowth molecular sieves are describedin the U.S. patent application Ser. No. 09/924,016 filed Aug. 7, 2001and International Publication No. WO 98/15496 published Apr. 16, 1998,both of which are herein fully incorporated by reference. For example,SAPO-18, AlPO-18 and RUW-18 have an AEI framework-type, and SAPO-34 hasa CHA framework-type. Thus the molecular sieve used herein may compriseat least one intergrowth phase of AEI and CHA framework-types,especially where the ratio of CHA framework-type to AEI framework-type,as determined by the DIFFaX method disclosed in U.S. patent applicationSer. No. 09/924,106 filed Aug. 7, 2001, is greater than 1:1.

Molecular Sieve Synthesis

The synthesis of molecular sieves is described in many of the referencesdiscussed above. Generally, molecular sieves are synthesized by thehydrothermal crystallization of one or more of a source of aluminum, asource of phosphorus, a source of silicon and a templating agent, suchas a nitrogen containing organic compound. Typically, a combination ofsources of silicon, aluminum and phosphorus, optionally with one or moretemplating agents, is placed in a sealed pressure vessel, optionallylined with an inert plastic such as polytetrafluoroethylene, and heated,under a crystallization pressure and temperature, until a crystallinematerial is formed, and then recovered by filtration, centrifugationand/or decanting.

Non-limiting examples of silicon sources include silicates, fumedsilica, for example, Aerosil-200 available from Degussa Inc., New York,N.Y., and CAB-O-SIL M-5, organosilicon compounds such as tetraalkylorthosilicates, for example, tetramethyl orthosilicate (TMOS) andtetraethylorthosilicate (TEOS), colloidal silicas or aqueous suspensionsthereof, for example Ludox HS-40 sol available from E. I. du Pont deNemours, Wilmington, Del., silicic acid or any combination thereof.

Non-limiting examples of aluminum sources include aluminum alkoxides,for example aluminum isopropoxide, aluminum phosphate, aluminumhydroxide, sodium aluminate, pseudo-boehmite, gibbsite and aluminumtrichloride, or any combination thereof. A convenient source of aluminumis pseudo-boehmite, particularly when producing a silicoaluminophosphatemolecular sieve.

Non-limiting examples of phosphorus sources, which may also includealuminum-containing phosphorus compositions, include phosphoric acid,organic phosphates such as triethyl phosphate, and crystalline oramorphous aluminophosphates such as AlPO₄, phosphorus salts, orcombinations thereof. A convenient source of phosphorus is phosphoricacid, particularly when producing a silicoaluminophosphate.

Templating agents are generally compounds that contain elements of Group15 of the Periodic Table of Elements, particularly nitrogen, phosphorus,arsenic and antimony. Typical templating agents also contain at leastone alkyl or aryl group, such as an alkyl or aryl group having from 1 to10 carbon atoms, for example from 1 to 8 carbon atoms. Preferredtemplating agents are often nitrogen-containing compounds, such asamines, quaternary ammonium compounds and combinations thereof. Suitablequaternary ammonium compounds are represented by the general formulaR₄N⁺, where each R is hydrogen or a hydrocarbyl or substitutedhydrocarbyl group, preferably an alkyl group or an aryl group havingfrom 1 to 10 carbon atoms.

Non-limiting examples of templating agents include tetraalkyl ammoniumcompounds including salts thereof, such as tetramethyl ammoniumcompounds, tetraethyl ammonium compounds, tetrapropyl ammoniumcompounds, and tetrabutylammonium compounds, cyclohexylamine,morpholine, di-n-propylamine (DPA), tripropylamine, triethylamine (TEA),triethanolamine, piperidine, cyclohexylamine, 2-methylpyridine,N,N-dimethylbenzylamine, N,N-diethylethanolamine, dicyclohexylamine,N,N-dimethylethanolamine, choline, N,N′-dimethylpiperazine,1,4-diazabicyclo(2,2,2)octane, N′,N′,N,N-tetramethyl-(1,6)hexanediamine,N-methyldiethanolamine, N-methyl-ethanolamine, N-methyl piperidine,3-methyl-piperidine, N-methylcyclohexylamine, 3-methylpyridine,4-methyl-pyridine, quinuclidine, N,N′-dimethyl-1,4-diazabicyclo(2,2,2)octane ion; di-n-butylamine, neopentylamine, di-n-pentylamine,isopropylamine, t-butyl-amine, ethylenediamine, pyrrolidine, and2-imidazolidone.

The pH of the synthesis mixture containing at a minimum a silicon-,aluminum-, and/or phosphorus-composition, and a templating agent, isgenerally in the range of from 2 to 10, such as from 4 to 9, for examplefrom 5 to 8.

Generally, the synthesis mixture described above is sealed in a vesseland heated, preferably under autogenous pressure, to a temperature inthe range of from about 80° C. to about 250° C., such as from about 100°C. to about 250° C., for example from about 125° C. to about 225° C.,such as from about 150° C. to about 180° C.

In one embodiment, the synthesis of a molecular sieve is aided by seedsfrom another or the same framework type molecular sieve.

The time required to form the crystalline product is usually dependenton the temperature and can vary from immediately up to several weeks.Typically the crystallization time is from about 30 minutes to around 2weeks, such as from about 45 minutes to about 240 hours, for examplefrom about 1 hour to about 120 hours. The hydrothermal crystallizationmay be carried out with or without agitation or stirring.

Once the crystalline molecular sieve product is formed, usually in aslurry state, it may be recovered by any standard technique well knownin the art, for example, by centrifugation or filtration. The recoveredcrystalline product may then be washed, such as with water, and thendried, such as in air.

One method for crystallization involves producing an aqueous reactionmixture containing an excess amount of a templating agent, subjectingthe mixture to crystallization under hydrothermal conditions,establishing an equilibrium between molecular sieve formation anddissolution, and then, removing some of the excess templating agentand/or organic base to inhibit dissolution of the molecular sieve. Seefor example U.S. Pat. No. 5,296,208, which is herein fully incorporatedby reference.

Other methods for synthesizing molecular sieves or modifying molecularsieves are described in U.S. Pat. No. 5,879,655 (controlling the ratioof the templating agent to phosphorus), U.S. Pat. No. 6,005,155 (use ofa modifier without a salt), U.S. Pat. No. 5,475,182 (acid extraction),U.S. Pat. No. 5,962,762 (treatment with transition metal), U.S. Pat.Nos. 5,925,586 and 6,153,552 (phosphorus modified), U.S. Pat. No.5,925,800 (monolith supported), U.S. Pat. No. 5,932,512 (fluorinetreated), U.S. Pat. No. 6,046,373 (electromagnetic wave treated ormodified), U.S. Pat. No. 6,051,746 (polynuclear aromatic modifier), U.S.Pat. No. 6,225,254 (heating template), PCT WO 01/36329 published May 25,2001 (surfactant synthesis), PCT WO 01/25151 published Apr. 12, 2001(staged acid addition), PCT WO 01/60746 published Aug. 23, 2001 (siliconoil), U.S. patent application Ser. No. 09/929,949 filed Aug. 15, 2001(cooling molecular sieve), U.S. patent application Ser. No. 09/615,526filed Jul. 13, 2000 (metal impregnation including copper), U.S. patentapplication Ser. No. 09/672,469 filed Sep. 28, 2000 (conductivemicrofilter), and U.S. patent application Ser. No. 09/754,812 filed Jan.4, 2001 (freeze drying the molecular sieve), which are all herein fullyincorporated by reference.

Where a templating agent is used in the synthesis of the molecularsieve, any templating agent retained in the product may be removed aftercrystallization by numerous well known techniques, for example, bycalcination. Calcination involves contacting the molecular sievecontaining the templating agent with a gas, preferably containingoxygen, at any desired concentration at an elevated temperaturesufficient to either partially or completely remove the templatingagent.

Aluminosilicate and silicoaluminophosphate molecular sieves have eithera high silicon (Si) to aluminum (Al) ratio or a low silicon to aluminumratio, however, a low Si/Al ratio is preferred for SAPO synthesis. Inone embodiment, the molecular sieve has a Si/Al ratio less than 0.65,such as less than 0.40, for example less than 0.32, and particularlyless than 0.20. In another embodiment the molecular sieve has a Si/Alratio in the range of from about 0.65 to about 0.10, such as from about0.40 to about 0.10, for example from about 0.32 to about 0.10, andparticularly from about 0.32 to about 0.15.

Active Metal Oxides

Active metal oxides useful herein are those metal oxides, different fromtypical binders and/or matrix materials, that, when used in combinationwith a molecular sieve, provide benefits in catalytic conversionprocesses. Preferred active metal oxides are those metal oxides having aGroup 4 metal, such as zirconium and/or hafnium, either alone or incombination with a Group 2 (for example magnesium, calcium, strontiumand barium) and/or a Group 3 metal (including the Lanthanides andActinides) oxide (for example yttrium, scandium and lanthanum). The mostpreferred active Group 4 metal oxide is an active zirconium metal oxide,either alone or in combination with calcium oxide, barium oxide,lanthanum oxide and/or yttrium oxide. In general, oxides of silicon,aluminum, and combinations thereof are not preferred.

In one embodiment, active metal oxides are those metal oxides, differentfrom typical binders and/or matrix materials that, when used incombination with a molecular sieve in a catalyst composition, areeffective in extending of the useful life of the catalyst composition.Quantification of the extension in catalyst life is determined by theLifetime Enhancement Index (LEI) as defined by the following equation:${LEI} = \frac{{Lifetime}\quad{of}{\quad\quad}{Catalyst}\quad{in}\quad{Combination}\quad{with}\quad{Active}\quad{Metal}\quad{Oxide}}{{Lifetime}\quad{of}\quad{Catalyst}}$where the lifetime of the catalyst or catalyst composition, in the sameprocess under the same conditions, is the cumulative amount of feedstockprocessed per gram of catalyst composition until the conversion offeedstock by the catalyst composition falls below some defined level,for example 10%. An inactive metal oxide will have little to no effecton the lifetime of the catalyst composition, or will shorten thelifetime of the catalyst composition, and will therefore have a LEI lessthan or equal to 1. Thus active metal oxides of the invention are thosemetal oxides, different from typical binders and/or matrix materials,that, when used in combination with a molecular sieve, provide amolecular sieve catalyst composition that has a LEI greater than 1. Bydefinition, a molecular sieve catalyst composition that has not beencombined with an active metal oxide will have a LEI equal to 1.0.

It is found that, by including an active metal oxide in combination witha molecular sieve, a catalyst composition can be produced having an LEIin the range of from greater than 1 to 20, such as from about 1.5 toabout 10. Typically catalyst compositions according to the inventionexhibit LEI values greater than 1.1, for example in the range of fromabout 1.2 to 15, and more particularly greater than 1.3, such as greaterthan 1.5, such as greater than 1.7, such as greater than 2.

In one embodiment, the active metal oxide when combined with a molecularsieve in a catalyst composition enhances the lifetime of the catalystcomposition in the conversion of a feedstock comprising methanol,preferably into one or more olefin(s).

In particular, the metal oxides useful herein have an uptake of carbondioxide at 100° C. of at least 0.03 mg/m² of the metal oxide, such as atleast 0.035 mg/m² of the metal oxide. Although the upper limit on thecarbon dioxide uptake of the metal oxide is not critical, in general themetal oxides useful herein will have a carbon dioxide at 100° C. of lessthan 10 mg/m² of the metal oxide, such as less than 5 mg/m² of the metaloxide. Typically, the metal oxides useful herein have a carbon dioxideuptake of 0.04 to 0.2 mg/m² of the metal oxide.

In order to determine the carbon dioxide uptake of a metal oxide, thefollowing procedure is adopted. A sample of the metal oxide isdehydrated by heating the sample to about 200° C. to 500° C. in flowingair until a constant weight, the “dry weight”, is obtained. Thetemperature of the sample is then reduced to 100° C. and carbon dioxideis passed over the sample, either continuously or in pulses, again untilconstant weight is obtained. The increase in weight of the sample interms of mg/mg of the sample based on the dry weight of the sample isthe amount of adsorbed carbon dioxide.

In the Examples reported below, the carbon dioxide adsorption ismeasured using a Mettler TGA/SDTA 851 thermogravimetric analysis systemunder ambient pressure. The metal oxide sample is dehydrated in flowingair to about 500° C. for one hour. The temperature of the sample is thenreduced in flowing helium to 100° C. After the sample has equilibratedat the desired adsorption temperature in flowing helium, the sample issubjected to 20 separate pulses (about 12 seconds/pulse) of a gaseousmixture comprising 10-weight % carbon dioxide with the remainder beinghelium. After each pulse of the adsorbing gas the metal oxide sample isflushed with flowing helium for 3 minutes. The increase in weight of thesample in terms of mg/mg adsorbent based on the adsorbent weight aftertreatment at 500° C. is the amount of adsorbed carbon dioxide. Thesurface area of the sample is measured in accordance with the method ofBrunauer, Emmett, and Teller (BET) published as ASTM D 3663 to providethe carbon dioxide uptake in terms of mg carbon dioxide/m² of the metaloxide.

In one embodiment, the active metal oxide(s) has a BET surface area ofgreater than 10 m²/g, such as greater than 10 m²/g to about 300 m²/g. Inanother embodiment, the active metal oxide(s) has a BET surface areagreater than 20 m²/g, such as from 20 m²/g to 250 m²/g. In yet anotherembodiment, the active metal oxide(s) has a BET surface area greaterthan 25 m²/g, such as from 25 m²/g to about 200 m²/g. In a preferredembodiment, the active metal oxide(s) includes a zirconium oxide havinga BET surface area greater than 20 m²/g, such as greater than 25 m²/gand particularly greater than 30 m²/g

The active metal oxide(s) used herein can be prepared using a variety ofmethods. It is preferable that the active metal oxide is made from anactive metal oxide precursor, such as a metal salt, such as a halide,nitrate sulfate or acetate. Other suitable sources of the metal oxideinclude compounds that form the metal oxide during calcination, such asoxychlorides and nitrates. Alkoxides are also suitable sources of theGroup 4 metal oxide, for example zirconium n-propoxide. A preferredsource of the Group 4 metal oxide is hydrated zirconia. The expression,hydrated zirconia, is intended to connote a material comprisingzirconium atoms covalently linked to other zirconium atoms via bridgingoxygen atoms, and further comprising available hydroxyl groups.

In one embodiment, the hydrated zirconia is hydrothermally treated underconditions that include a temperature of at least 80° C., preferably atleast 100° C. The hydrothermal treatment typically takes place in asealed vessel at greater than atmospheric pressure. However, a preferredmode of treatment involves the use of an open vessel under refluxconditions. Agitation of hydrated Group 4 metal oxide in a liquidmedium, for example, by the action of refluxing liquid and/or stirring,promotes the effective interaction of the hydrated oxide with the liquidmedium. The duration of the contact of the hydrated oxide with theliquid medium is conveniently at least 1 hour, such as at least 8 hours.The liquid medium for this treatment typically has a pH of about 6 orgreater, such as 8 or greater. Non-limiting examples of suitable liquidmedia include water, hydroxide solutions (including hydroxides of NH₄ ⁺,Na⁺, K⁺, Mg²⁺, and Ca²⁺), carbonate and bicarbonate solutions (includingcarbonates and bicarbonates of NH₄ ⁺, Na⁺, K⁺, Mg²⁺, and Ca²⁺), pyridineand its derivatives, and alkyl/hydroxyl amines.

In another embodiment, the active metal oxide is prepared, for example,by subjecting a liquid solution, such as an aqueous solution, comprisinga source of ions of a Group 4 metal to conditions sufficient to causeprecipitation of a hydrated precursor of the solid oxide material, suchas by the addition of a precipitating reagent to the solution.Conveniently, the precipitation is conducted at a pH above 7. Forexample, the precipitating agent may be a base such as sodium hydroxideor ammonium hydroxide.

When a mixture of a Group 4 metal oxide with a Group 2 and/or 3 metaloxide is to be prepared, a first liquid solution comprising a source ofions of a Group 4 metal can be combined with a second liquid solutioncomprising a source of ions of a Group 2 and/or Group 3 metal. Thiscombination of two solutions can take place under conditions sufficientto cause co-precipitation of the mixed oxide material as a solid fromthe liquid medium. Alternatively, the source of ions of the Group 4metal and the source of ions of the Group 2 and/or Group 3 metal may becombined into a single solution. This solution may then be subjected toconditions sufficient to cause co-precipitation of a hydrated precursorof the solid mixed oxide material, such as by the addition of aprecipitating reagent to the solution.

The temperature at which the liquid medium is maintained during theprecipitation is generally less than about 200° C., such as in the rangeof from about 0° C. to about 200° C. A particular range of temperaturesfor precipitation is from about 20° C. to about 100° C. The resultinggel is preferably then hydrothermally treated at temperatures of atleast 80° C., preferably at least 100° C. The hydrothermal treatmenttypically takes place in a vessel at atmospheric pressure. The gel, inone embodiment, is hydrothermally treated for up to 10 days, such as upto 5 days, for example up to 3 days.

The hydrated precursor to the metal oxide(s) is then recovered, forexample by filtration or centrifugation, and washed and dried. Theresulting material can then be calcined, such as in an oxidizingatmosphere, at a temperature of at least 400° C., such as at least 500°C., for example from about 600° C. to about 900° C., and particularlyfrom about 650° C. to about 800° C., to form the active metal oxide oractive mixed metal oxide. The calcination time is typically up to 48hours, such as for about 0.5 to 24 hours, for example for about 1.0 to10 hours. In one embodiment, calcination is carried out at about 700° C.for about 1 to about 3 hours.

In another embodiment, the Group 4 metal oxide and the Group 2 and/orGroup 3 metal oxide are made separately and then contacted together toform the mixed metal oxide that is then contacted with the molecularsieve. For example, the Group 4 metal oxide can be contacted with themolecular sieve prior to introducing the Group 2 and/or Group 3 metaloxide or alternatively, the Group 2 and/or Group 3 metal oxide can becontacted with the molecular sieve prior to introducing the Group 4metal oxide.

Where the catalyst composition comprises a Group 4 metal oxide and aGroup 3 metal oxide, the mole ratio of the Group 4 metal oxide to theGroup 3 metal oxide may be in the range of from 1000:1 to 1:1, such asfrom about 500:1 to 2:1, such as from about 100:1 to about 3:1, such asfrom about 75:1 to about 5:1 based on the total moles of the Group 4 andGroup 3 metal oxides. In addition, the catalyst composition can containfrom 1 to 25%, such as from 1 to 20%, such as from 1 to 15%, by weightof Group 3 metal based on the total weight of the mixed metal oxide,particularly where the Group 3 metal oxide is a lanthanum or yttriummetal oxide and the Group 4 metal oxide is a zirconium metal oxide.

Where the catalyst composition comprises a Group 4 metal oxide and aGroup 2 metal oxide, the mole ratio of the Group 4 metal oxide to theGroup 2 metal oxide may be in the range of from 1000:1 to 1:2, such asfrom about 500:1 to 2:3, such as from about 100:1 to about 1:1, such asfrom about 50:1 to about 2:1, based on the total moles of the Group 4and Group 2 metal oxides. In addition, the catalyst composition cancontain from 1 to 25%, such as from 1 to 20%, such as from 1 to 15%, byweight of Group 2 metal based on the total weight of the mixed metaloxide, particularly where the Group 2 metal oxide is calcium oxide andthe Group 4 metal oxide is a zirconium metal oxide.

Catalyst Composition

The catalyst composition of the invention includes any one of themolecular sieves previously described and one or more of the activemetal oxides described above, optionally with a binder and/or matrixmaterial different from the active metal oxide(s). Typically, the weightratio of the molecular sieve to the active metal oxide(s) in thecatalyst composition is in the range of from 5 weight percent to 800weight percent, such as from 10 weight percent to 600 weight percent,particularly from 20 weight percent to 500 weight percent, and moreparticularly from 30 weight percent to 400 weight percent.

There are many different binders that are useful in forming catalystcompositions. Non-limiting examples of binders that are useful alone orin combination include various types of hydrated alumina, silicas,and/or other inorganic oxide sols. One preferred alumina containing solis aluminum chlorhydrol. The inorganic oxide sol acts like glue bindingthe synthesized molecular sieves and other materials such as the matrixtogether, particularly after thermal treatment. Upon heating, theinorganic oxide sol, preferably having a low viscosity, is convertedinto an inorganic oxide binder component. For example, an alumina solwill convert to an aluminum oxide binder following heat treatment.

Aluminum chlorhydrol, a hydroxylated aluminum based sol containing achloride counter ion, has the general formula ofAl_(m)O_(n)(OH)_(o)Cl_(p)•x(H₂O) wherein m is 1 to 20, n is 1 to 8, o is5 to 40, p is 2 to 15, and x is 0 to 30. In one embodiment, the binderis Al₁₃O₄(OH)₂₄Cl₇•12(H₂O) as is described in G. M. Wolterman, et al.,Stud. Surf. Sci. and Catal., 76, pages 105-144 (1993), which is hereinincorporated by reference. In another embodiment, one or more bindersare combined with one or more other non-limiting examples of aluminamaterials such as aluminum oxyhydroxide, γ-alumina, boehmite, diaspore,and transitional aluminas such as α-alumina, β-alumina, γ-alumina,δ-alumina, ε-alumina, κ-alumina, and ρ-alumina, aluminum trihydroxide,such as gibbsite, bayerite, nordstrandite, doyelite, and mixturesthereof.

In another embodiment, the binder is an alumina sol, predominantlycomprising aluminum oxide, optionally including some silicon. In yetanother embodiment, the binder is peptized alumina made by treating analumina hydrate, such as pseudobohemite, with an acid, preferably anacid that does not contain a halogen, to prepare a sol or aluminum ionsolution. Non-limiting examples of commercially available colloidalalumina sols include Nalco 8676 available from Nalco Chemical Co.,Naperville, Ill., and Nyacol AL20DW available from Nyacol NanoTechnologies, Inc., Ashland, Mass.

Where the catalyst composition contains a matrix material, this ispreferably different from the active metal oxide and any binder. Matrixmaterials are typically effective in reducing overall catalyst cost,acting as thermal sinks to assist in shielding heat from the catalystcomposition for example during regeneration, densifying the catalystcomposition, and increasing catalyst strength such as crush strength andattrition resistance.

Non-limiting examples of matrix materials include one or more non-activemetal oxides including beryllia, quartz, silica or sols, and mixturesthereof, for example silica-magnesia, silica-zirconia, silica-titania,silica-alumina and silica-alumina-thoria. In an embodiment, matrixmaterials are natural clays such as those from the families ofmontmorillonite and kaolin. These natural clays include subbentonitesand those kaolins known as, for example, Dixie, McNamee, Georgia andFlorida clays. Non-limiting examples of other matrix materials includehaloysite, kaolinite, dickite, nacrite, or anauxite. The matrixmaterial, such as a clay, may be subjected to well known modificationprocesses such as calcination and/or acid treatment and/or chemicaltreatment.

In a preferred embodiment, the matrix material is a clay or a clay-typecomposition, particularly a clay or clay-type composition having a lowiron or titania content, and most preferably the matrix material iskaolin. Kaolin has been found to form a pumpable, high solids contentslurry, to have a low fresh surface area, and to pack together easilydue to its platelet structure. A preferred average particle size of thematrix material, most preferably kaolin, is from about 0.1 μm to about0.6 μm with a D₉₀ particle size distribution of less than about 1 μm.

Where the catalyst composition contains a binder or matrix material, thecatalyst composition typically contains from about 1% to about 80%, suchas from about 5% to about 60%, and particularly from about 5% to about50%, by weight of the molecular sieve based on the total weight of thecatalyst composition.

Where the catalyst composition contains a binder and a matrix material,the weight ratio of the binder to the matrix material is typically from1:15 to 1:5, such as from 1:10 to 1:4, and particularly from 1:6 to 1:5.The amount of binder is typically from about 2% by weight to about 30%by weight, such as from about 5% by weight to about 20% by weight, andparticularly from about 7% by weight to about 15% by weight, based onthe total weight of the binder, the molecular sieve and matrix material.It has been found that a higher sieve content and lower matrix contentincreases the molecular sieve catalyst composition performance, whereasa lower sieve content and higher matrix content improves the attritionresistance of the composition.

The catalyst composition typically has a density in the range of from0.5 g/cc to 5 g/cc, such as from 0.6 g/cc to 5 g/cc, for example from0.7 g/cc to 4 g/cc, particularly in the range of from 0.8 g/cc to 3g/cc.

Method of Making the Catalyst Composition

In making the catalyst composition, the molecular sieve is first formedand is then physically mixed with the active metal oxide, preferably ina substantially dry, dried, or calcined state. Most preferably themolecular sieve and active metal oxides are physically mixed in theircalcined state. Without being bound by any particular theory, it isbelieved that intimate mixing of the molecular sieve and one or moreactive metal oxides improves conversion processes using the molecularsieve composition and catalyst composition of the invention. Intimatemixing can be achieved by any method known in the art, such as mixingwith a mixer muller, drum mixer, ribbon/paddle blender, kneader, or thelike. Chemical reaction between the molecular sieve and the metaloxide(s) is unnecessary and, in general, is not preferred.

Where the catalyst composition contains a matrix and/or binder, themolecular sieve is conveniently initially formulated into a catalystprecursor with the matrix and/or binder and the active metal oxide isthen combined with the formulated precursor. The active metal oxide canbe added as unsupported particles or can be added in combination with asupport, such as a binder or matrix material. The resultant catalystcomposition can then be formed into useful shaped and sized particles bywell-known techniques such as spray drying, pelletizing, extrusion, andthe like.

In one embodiment, the molecular sieve composition and the matrixmaterial, optionally with a binder, are combined with a liquid to form aslurry and then mixed, preferably rigorously mixed, to produce asubstantially homogeneous mixture containing the molecular sievecomposition. Non-limiting examples of suitable liquids include one or acombination of water, alcohol, ketones, aldehydes, and/or esters. Themost preferred liquid is water. In one embodiment, the slurry iscolloid-milled for a period of time sufficient to produce the desiredslurry texture, sub-particle size, and/or sub-particle sizedistribution.

The molecular sieve composition and matrix material, and the optionalbinder, can be combined in the same or different liquids, and can becombined in any order, together, simultaneously, sequentially, or acombination thereof. In the preferred embodiment, the same liquid,preferably water is used. The molecular sieve composition, matrixmaterial, and optional binder, are combined in a liquid as solids,substantially dry or in a dried form, or as slurries, together orseparately. If solids are added together as dry or substantially driedsolids, it is preferable to add a limited and/or controlled amount ofliquid.

In one embodiment, the slurry of the molecular sieve composition, binderand matrix materials is mixed or milled to achieve a sufficientlyuniform slurry of sub-particles of the molecular sieve catalystcomposition that is then fed to a forming unit that produces themolecular sieve catalyst composition. In a preferred embodiment, theforming unit is spray dryer. Typically, the forming unit is maintainedat a temperature sufficient to remove most of the liquid from theslurry, and from the resulting molecular sieve catalyst composition. Theresulting catalyst composition when formed in this way takes the form ofmicrospheres.

When a spray drier is used as the forming unit, typically, the slurry ofthe molecular sieve composition and matrix material, and optionally abinder, is co-fed to the spray drying volume with a drying gas with anaverage inlet temperature ranging from 200° C. to 550° C., and acombined outlet temperature ranging from 100° C. to about 225° C. In anembodiment, the average diameter of the spray dried formed catalystcomposition is from about 40 μm to about 300 μm, such as from about 50μm to about 250 μm, for example from about 50 μm to about 200 μm, andconveniently from about 65 μm to about 90 μm.

Other methods for forming a molecular sieve catalyst composition aredescribed in U.S. patent application Ser. No. 09/617,714 filed Jul. 17,2000 (spray drying using a recycled molecular sieve catalystcomposition), which is herein incorporated by reference.

Once the molecular sieve catalyst composition is formed in asubstantially dry or dried state, to further harden and/or activate theformed catalyst composition, a heat treatment such as calcination, at anelevated temperature is usually performed. Typical calcinationtemperatures are in the range from about 400° C. to about 1,000° C.,such as from about 500° C. to about 800° C., such as from about 550° C.to about 700° C. Typical calcination environments are air (which mayinclude a small amount of water vapor), nitrogen, helium, flue gas(combustion product lean in oxygen), or any combination thereof.

In a preferred embodiment, the catalyst composition is heated innitrogen at a temperature of from about 600° C. to about 700° C. Heatingis carried out for a period of time typically from 30 minutes to 15hours, such as from 1 hour to about 10 hours, for example from about 1hour to about 5 hours, and particularly from about 2 hours to about 4hours.

Process for Using the Molecular Sieve Catalyst Compositions

The catalyst compositions described above are useful in a variety ofprocesses including cracking, of for example a naphtha feed to lightolefin(s) (U.S. Pat. No. 6,300,537) or higher molecular weight (MW)hydrocarbons to lower MW hydrocarbons; hydrocracking, of for exampleheavy petroleum and/or cyclic feedstock; isomerization, of for examplearomatics such as xylene; polymerization, of for example one or moreolefin(s) to produce a polymer product; reforming; hydrogenation;dehydrogenation; dewaxing, of for example hydrocarbons to removestraight chain paraffins; absorption, of for example alkyl aromaticcompounds for separating out isomers thereof; alkylation, of for examplearomatic hydrocarbons such as benzene and alkyl benzene, optionally withpropylene to produce cumene or with long chain olefins; transalkylation,of for example a combination of aromatic and polyalkylaromatichydrocarbons; dealkylation; hydrodecylization; disproportionation, offor example toluene to make benzene and paraxylene; oligomerization, offor example straight and branched chain olefin(s); anddehydrocyclization.

Preferred processes include processes for converting naphtha to highlyaromatic mixtures; converting light olefin(s) to gasoline, distillatesand lubricants; converting oxygenates to olefin(s); converting lightparaffins to olefins and/or aromatics; and converting unsaturatedhydrocarbons (ethylene and/or acetylene) to aldehydes for conversioninto alcohols, acids and esters.

The most preferred process of the invention is a process directed to theconversion of a feedstock to one or more olefin(s). Typically, thefeedstock contains one or more aliphatic-containing compounds such thatthe aliphatic moiety contains from 1 to about 50 carbon atoms, such asfrom 1 to 20 carbon atoms, for example from 1 to 10 carbon atoms, andparticularly from 1 to 4 carbon atoms.

Non-limiting examples of aliphatic-containing compounds include alcoholssuch as methanol and ethanol, alkyl mercaptans such as methyl mercaptanand ethyl mercaptan, alkyl sulfides such as methyl sulfide, alkylaminessuch as methylamine, alkyl ethers such as dimethyl ether, diethyl etherand methylethyl ether, alkyl halides such as methyl chloride and ethylchloride, alkyl ketones such as dimethyl ketone, formaldehydes, andvarious acids such as acetic acid.

In a preferred embodiment of the process of the invention, the feedstockcontains one or more oxygenates, more specifically, one or more organiccompound(s) containing at least one oxygen atom. In the most preferredembodiment of the process of invention, the oxygenate in the feedstockis one or more alcohol(s), preferably aliphatic alcohol(s) where thealiphatic moiety of the alcohol(s) has from 1 to 20 carbon atoms,preferably from 1 to 10 carbon atoms, and most preferably from 1 to 4carbon atoms. The alcohols useful as feedstock in the process of theinvention include lower straight and branched chain aliphatic alcoholsand their unsaturated counterparts.

Non-limiting examples of oxygenates include methanol, ethanol,n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethylether, di-isopropyl ether, formaldehyde, dimethyl carbonate, dimethylketone, acetic acid, and mixtures thereof.

In the most preferred embodiment, the feedstock is selected from one ormore of methanol, ethanol, dimethyl ether, diethyl ether or acombination thereof, more preferably methanol and dimethyl ether, andmost preferably methanol.

The various feedstocks discussed above, particularly a feedstockcontaining an oxygenate, more particularly a feedstock containing analcohol, is converted primarily into one or more olefin(s). Theolefin(s) produced from the feedstock typically have from 2 to 30 carbonatoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbonatoms, still more preferably 2 to 4 carbons atoms, and most preferablyare ethylene and/or propylene.

The catalyst composition of the invention is particularly useful in theprocess that is generally referred to as the gas-to-olefins (GTO)process or alternatively, the methanol-to-olefins (MTO) process. In thisprocess, an oxygenated feedstock, most preferably a methanol-containingfeedstock, is converted in the presence of a molecular sieve catalystcomposition into one or more olefin(s), preferably and predominantly,ethylene and/or propylene.

Using the catalyst composition of the invention for the conversion of afeedstock, preferably a feedstock containing one or more oxygenates, theamount of olefin(s) produced based on the total weight of hydrocarbonproduced is greater than 50 weight percent, typically greater than 60weight percent, such as greater than 70 weight percent, and preferablygreater than 80 weight percent. Moreover, the amount of ethylene and/orpropylene produced based on the total weight of hydrocarbon productproduced is greater than 40 weight percent, typically greater than 50weight percent, for example greater than 65 weight percent, andpreferably greater than 78 weight percent. Typically, the amountethylene produced in weight percent based on the total weight ofhydrocarbon product produced, is greater than 20 weight percent, such asgreater than 30 weight percent, for example greater than 40 weightpercent. In addition, the amount of propylene produced in weight percentbased on the total weight of hydrocarbon product produced is typicallygreater than 20 weight percent, such as greater than 25 weight percent,for example greater than 30 weight percent, and preferably greater than35 weight percent.

Using the catalyst composition of the invention for the conversion of afeedstock comprising methanol and dimethylether to ethylene andpropylene, it is found that the production of ethane and propane isreduced by greater than 10%, such as greater than 20%, for examplegreater than 30%, and particularly in the range of from about 30% to 40%compared to a similar catalyst composition at the same conversionconditions but without the active metal oxide component(s).

In addition to the oxygenate component, such as methanol, the feedstockmay contains one or more diluent(s), which are generally non-reactive tothe feedstock or molecular sieve catalyst composition and are typicallyused to reduce the concentration of the feedstock. Non-limiting examplesof diluents include helium, argon, nitrogen, carbon monoxide, carbondioxide, water, essentially non-reactive paraffins (especially alkanessuch as methane, ethane, and propane), essentially non-reactive aromaticcompounds, and mixtures thereof. The most preferred diluents are waterand nitrogen, with water being particularly preferred.

The diluent, for example water, may be used either in a liquid or avapor form, or a combination thereof. The diluent may be either addeddirectly to the feedstock entering a reactor or added directly to thereactor, or added with the molecular sieve catalyst composition.

The present process can be conducted over a wide range of temperatures,such as in the range of from about 200° C. to about 1000° C., forexample from about 250° C. to about 800° C., including from about 250°C. to about 750° C., conveniently from about 300° C. to about 650° C.,typically from about 350° C. to about 600° C. and particularly fromabout 350° C. to about 550° C.

Similarly, the present process can be conducted over a wide range ofpressures including autogenous pressure. Typically the partial pressureof the feedstock exclusive of any diluent therein employed in theprocess is in the range of from about 0.1 kPaa to about 5 MPaa, such asfrom about 5 kPaa to about 1 MPaa, and conveniently from about 20 kPaato about 500 kPaa.

The weight hourly space velocity (WHSV), defined as the total weight offeedstock excluding any diluents per hour per weight of molecular sievein the catalyst composition, typically ranges from about 1 hr−1 to about5000 hr−1, such as from about 2 hr−1 to about 3000 hr−1, for examplefrom about 5 hr−1 to about 1500 hr−1, and conveniently from about 10hr−1 to about 1000 hr−1. In one embodiment, the WHSV is greater than 20hr−1 and, where feedstock contains methanol and/or dimethyl ether, is inthe range of from about 20 hr−1 to about 300 hr−1.

Where the process is conducted in a fluidized bed, the superficial gasvelocity (SGV) of the feedstock including diluent and reaction productswithin the reactor system, and particularly within a riser reactor(s),is at least 0.1 meter per second (m/sec), such as greater than 0.5m/sec, such as greater than 1 m/sec, for example greater than 2 m/sec,conveniently greater than 3 m/sec, and typically greater than 4 m/sec.See for example U.S. patent application Ser. No. 09/708,753 filed Nov.8, 2000, which is herein incorporated by reference.

The process of the invention is conveniently conducted as a fixed bedprocess, or more typically as a fluidized bed process (including aturbulent bed process), such as a continuous fluidized bed process, andparticularly a continuous high velocity fluidized bed process.

The process can take place in a variety of catalytic reactors such ashybrid reactors that have a dense bed or fixed bed reaction zones and/orfast fluidized bed reaction zones coupled together, circulatingfluidized bed reactors, riser reactors, and the like. Suitableconventional reactor types are described in for example U.S. Pat. No.4,076,796, U.S. Pat. No. 6,287,522 (dual riser), and FluidizationEngineering, D. Kunii and O. Levenspiel, Robert E. Krieger PublishingCompany, New York, N.Y. 1977, which are all herein fully incorporated byreference.

The preferred reactor types are riser reactors generally described inRiser Reactor, Fluidization and Fluid-Particle Systems, pages 48 to 59,F. A. Zenz and D. F. Othmo, Reinhold Publishing Corporation, New York,1960, and U.S. Pat. No. 6,166,282 (fast-fluidized bed reactor), and U.S.patent application Ser. No. 09/564,613 filed May 4, 2000 (multiple riserreactor), which are all herein fully incorporated by reference.

In one practical embodiment, the process is conducted as a fluidized bedprocess or high velocity fluidized bed process utilizing a reactorsystem, a regeneration system and a recovery system.

In such a process the reactor system would conveniently include a fluidbed reactor system having a first reaction zone within one or more riserreactor(s) and a second reaction zone within at least one disengagingvessel, typically comprising one or more cyclones. In one embodiment,the one or more riser reactor(s) and disengaging vessel are containedwithin a single reactor vessel. Fresh feedstock, preferably containingone or more oxygenates, optionally with one or more diluent(s), is fedto the one or more riser reactor(s) into which a molecular sievecatalyst composition or coked version thereof is introduced. In oneembodiment, prior to being introduced to the riser reactor(s), themolecular sieve catalyst composition or coked version thereof iscontacted with a liquid, preferably water or methanol, and/or a gas, forexample, an inert gas such as nitrogen.

In an embodiment, the amount of fresh feedstock fed as a liquid and/or avapor to the reactor system is in the range of from 0.1 weight percentto about 85 weight percent, such as from about 1 weight percent to about75 weight percent, more typically from about 5 weight percent to about65 weight percent based on the total weight of the feedstock includingany diluent contained therein. The liquid and vapor feedstocks may bethe same composition, or may contain varying proportions of the same ordifferent feedstocks with the same or different diluents.

The feedstock entering the reactor system is preferably converted,partially or fully, in the first reactor zone into a gaseous effluentthat enters the disengaging vessel along with the coked catalystcomposition. In the preferred embodiment, cyclone(s) are provided withinthe disengaging vessel to separate the coked catalyst composition fromthe gaseous effluent containing one or more olefin(s) within thedisengaging vessel. Although cyclones are preferred, gravity effectswithin the disengaging vessel can also be used to separate the catalystcomposition from the gaseous effluent. Other methods for separating thecatalyst composition from the gaseous effluent include the use ofplates, caps, elbows, and the like.

In one embodiment, the disengaging vessel includes a stripping zone,typically in a lower portion of the disengaging vessel. In the strippingzone the coked catalyst composition is contacted with a gas, preferablyone or a combination of steam, methane, carbon dioxide, carbon monoxide,hydrogen, or an inert gas such as argon, preferably steam, to recoveradsorbed hydrocarbons from the coked catalyst composition that is thenintroduced to the regeneration system.

The coked catalyst composition is withdrawn from the disengaging vesseland introduced to the regeneration system. The regeneration systemcomprises a regenerator where the coked catalyst composition iscontacted with a regeneration medium, preferably a gas containingoxygen, under conventional regeneration conditions of temperature,pressure and residence time.

Non-limiting examples of suitable regeneration media include one or moreof oxygen, O3, SO3, N2O, NO, NO2, N2O5, air, air diluted with nitrogenor carbon dioxide, oxygen and water (U.S. Pat. No. 6,245,703), carbonmonoxide and/or hydrogen. Suitable regeneration conditions are thosecapable of burning coke from the coked catalyst composition, preferablyto a level less than 0.5 weight percent based on the total weight of thecoked molecular sieve catalyst composition entering the regenerationsystem. For example, the regeneration temperature may be in the range offrom about 200° C. to about 1500° C., such as from about 300° C. toabout 1000° C., for example from about 450° C. to about 750° C., andconveniently from about 550° C. to 700° C. The regeneration pressure maybe in the range of from about 15 psia (103 kPaa) to about 500 psia (3448kPaa), such as from about 20 psia (138 kPaa) to about 250 psia (1724kPaa), including from about 25 psia (172kPaa) to about 150 psia (1034kPaa), and conveniently from about 30 psia (207 kPaa) to about 60 psia(414 kPaa).

The residence time of the catalyst composition in the regenerator may bein the range of from about one minute to several hours, such as fromabout one minute to 100 minutes, and the volume of oxygen in theregeneration gas may be in the range of from about 0.01 mole percent toabout 5 mole percent based on the total volume of the gas.

The burning of coke in the regeneration step is an exothermic reaction,and in an embodiment, the temperature within the regeneration system iscontrolled by various techniques in the art including feeding a cooledgas to the regenerator vessel, operated either in a batch, continuous,or semi-continuous mode, or a combination thereof. A preferred techniqueinvolves withdrawing the regenerated catalyst composition from theregeneration system and passing it through a catalyst cooler to form acooled regenerated catalyst composition. The catalyst cooler, in anembodiment, is a heat exchanger that is located either internal orexternal to the regeneration system. Other methods for operating aregeneration system are disclosed in U.S. Pat. No. 6,290,916(controlling moisture), which is herein fully incorporated by reference.

The regenerated catalyst composition withdrawn from the regenerationsystem, preferably from a catalyst cooler, is combined with a freshmolecular sieve catalyst composition and/or re-circulated molecularsieve catalyst composition and/or feedstock and/or fresh gas or liquids,and returned to the riser reactor(s). In one embodiment, the regeneratedcatalyst composition withdrawn from the regeneration system is returnedto the riser reactor(s) directly, preferably after passing through acatalyst cooler. A carrier, such as an inert gas, feedstock vapor, steamor the like, may be used, semi-continuously or continuously, tofacilitate the introduction of the regenerated catalyst composition tothe reactor system, preferably to the one or more riser reactor(s).

By controlling the flow of the regenerated catalyst composition orcooled regenerated catalyst composition from the regeneration system tothe reactor system, the optimum level of coke on the molecular sievecatalyst composition entering the reactor is maintained. There are manytechniques for controlling the flow of a catalyst composition describedin Michael Louge, Experimental Techniques, Circulating Fluidized Beds,Grace, Avidan and Knowlton, eds., Blackie, 1997 (336-337), which isherein incorporated by reference.

Coke levels on the catalyst composition are measured by withdrawing thecatalyst composition from the conversion process and determining itscarbon content. Typical levels of coke on the molecular sieve catalystcomposition, after regeneration, are in the range of from 0.01 weightpercent to about 15 weight percent, such as from about 0.1 weightpercent to about 10 weight percent, for example from about 0.2 weightpercent to about 5 weight percent, and conveniently from about 0.3weight percent to about 2 weight percent based on the weight of themolecular sieve.

The gaseous effluent is withdrawn from the disengaging system and ispassed through a recovery system. There are many well known recoverysystems, techniques and sequences that are useful in separatingolefin(s) and purifying olefin(s) from the gaseous effluent. Recoverysystems generally comprise one or more or a combination of variousseparation, fractionation and/or distillation towers, columns,splitters, or trains, reaction systems such as ethylbenzene manufacture(U.S. Pat. No. 5,476,978) and other derivative processes such asaldehydes, ketones and ester manufacture (U.S. Pat. No. 5,675,041), andother associated equipment, for example various condensers, heatexchangers, refrigeration systems or chill trains, compressors,knock-out drums or pots, pumps, and the like.

Non-limiting examples of these towers, columns, splitters or trains usedalone or in combination include one or more of a demethanizer,preferably a high temperature demethanizer, a de-ethanizer, adepropanizer, a wash tower often referred to as a caustic wash towerand/or quench tower, absorbers, adsorbers, membranes, ethylene (C2)splitter, propylene (C3) splitter, butene (C4) splitter, and the like.

Various recovery systems useful for recovering predominantly olefin(s),preferably light olefin(s) such as ethylene, propylene and/or butene,are described in U.S. Pat. No. 5,960,643 (secondary rich ethylenestream), U.S. Pat. Nos. 5,019,143, 5,452,581 and 5,082,481 (membraneseparations), U.S. Pat. No. 5,672,197 (pressure dependent adsorbents),U.S. Pat. No. 6,069,288 (hydrogen removal), U.S. Pat. No. 5,904,880(recovered methanol to hydrogen and carbon dioxide in one step), U.S.Pat. No. 5,927,063 (recovered methanol to gas turbine power plant), andU.S. Pat. No. 6,121,504 (direct product quench), U.S. Pat. No. 6,121,503(high purity olefins without superfractionation), and U.S. Pat. No.6,293,998 (pressure swing adsorption), which are all herein fullyincorporated by reference.

Other recovery systems that include purification systems, for examplefor the purification of olefin(s), are described in Kirk-OthmerEncyclopedia of Chemical Technology, 4th Edition, Volume 9, John Wiley &Sons, 1996, pages 249-271 and 894-899, which is herein incorporated byreference. Purification systems are also described in for example, U.S.Pat. No. 6,271,428 (purification of a diolefin hydrocarbon stream), U.S.Pat. No. 6,293,999 (separating propylene from propane), and U.S. patentapplication Ser. No. 09/689,363 filed Oct. 20, 2000 (purge stream usinghydrating catalyst), which are herein incorporated by reference.

Generally accompanying most recovery systems is the production,generation or accumulation of additional products, by-products and/orcontaminants along with the preferred prime products. The preferredprime products, the light olefins, such as ethylene and propylene, aretypically purified for use in derivative manufacturing processes such aspolymerization processes. Therefore, in the most preferred embodiment ofthe recovery system, the recovery system also includes a purificationsystem. For example, the light olefin(s) produced particularly in a MTOprocess are passed through a purification system that removes low levelsof by-products or contaminants.

Non-limiting examples of contaminants and by-products include generallypolar compounds such as water, alcohols, carboxylic acids, ethers,carbon oxides, sulfur compounds such as hydrogen sulfide, carbonylsulfides and mercaptans, ammonia and other nitrogen compounds, arsine,phosphine and chlorides. Other contaminants or by-products includehydrogen and hydrocarbons such as acetylene, methyl acetylene,propadiene, butadiene and butyne.

Typically, in converting one or more oxygenates to olefin(s) having 2 or3 carbon atoms, a minor amount hydrocarbons, particularly olefin(s),having 4 or more carbon atoms is also produced. The amount of C4+hydrocarbons is normally less than 20 weight percent, such as less than10 weight percent, for example less than 5 weight percent, andparticularly less than 2 weight percent, based on the total weight ofthe effluent gas withdrawn from the process, excluding water. Typically,therefore the recovery system may include one or more reaction systemsfor converting the C4+ impurities to useful products.

Non-limiting examples of such reaction systems are described in U.S.Pat. No. 5,955,640 (converting a four carbon product into butene-1),U.S. Pat. No. 4,774,375 (isobutane and butene-2 oligomerized to analkylate gasoline), U.S. Pat. No. 6,049,017 (dimerization ofn-butylene), U.S. Pat. Nos. 4,287,369 and 5,763,678 (carbonylation orhydroformulation of higher olefins with carbon dioxide and hydrogenmaking carbonyl compounds), U.S. Pat. No. 4,542,252 (multistageadiabatic process), U.S. Pat. No. 5,634,354 (olefin-hydrogen recovery),and Cosyns, J. et al., Process for Upgrading C3, C4 and C5 OlefinicStreams, Pet. & Coal, Vol. 37, No. 4 (1995) (dimerizing or oligomerizingpropylene, butylene and pentylene), which are all herein fullyincorporated by reference.

The preferred light olefin(s) produced by any one of the processesdescribed above are high purity prime olefin(s) products that contain asingle carbon number olefin in an amount greater than 80 percent, suchas greater than 90 weight percent, such as greater than 95 weightpercent, for example at least about 99 weight percent, based on thetotal weight of the olefin.

In one practical embodiment, the process of the invention forms part ofan integrated process for producing light olefin(s) from a hydrocarbonfeedstock, preferably a gaseous hydrocarbon feedstock, particularlymethane and/or ethane. The first step in the process is passing thegaseous feedstock, preferably in combination with a water stream, to asyngas production zone to produce a synthesis gas (syngas) stream,typically comprising carbon dioxide, carbon monoxide and hydrogen.Syngas production is well known, and typical syngas temperatures are inthe range of from about 700° C. to about 1200° C. and syngas pressuresare in the range of from about 2 MPa to about 100 MPa. Synthesis gasstreams are produced from natural gas, petroleum liquids, andcarbonaceous materials such as coal, recycled plastic, municipal wasteor any other organic material. Preferably synthesis gas stream isproduced via steam reforming of natural gas.

The next step in the process involves contacting the synthesis gasstream generally with a heterogeneous catalyst, typically a copper basedcatalyst, to produce an oxygenate containing stream, often incombination with water. In one embodiment, the contacting step isconducted at temperature in the range of from about 150° C. to about450° C. and a pressure in the range of from about 5 MPa to about 10 MPa.

This oxygenate containing stream, or crude methanol, typically containsthe alcohol product and various other components such as ethers,particularly dimethyl ether, ketones, aldehydes, dissolved gases such ashydrogen methane, carbon oxide and nitrogen, and fuel oil. The oxygenatecontaining stream, crude methanol, in the preferred embodiment is passedthrough a well known purification processes, distillation, separationand fractionation, resulting in a purified oxygenate containing stream,for example, commercial Grade A and AA methanol.

The oxygenate containing stream or purified oxygenate containing stream,optionally with one or more diluents, can then be used as a feedstock ina process to produce light olefin(s), such as ethylene and/or propylene.Non-limiting examples of this integrated process are described in EP-B-0933 345, which is herein fully incorporated by reference.

In another more fully integrated process, that optionally is combinedwith the integrated processes described above, the olefin(s) producedare directed to, in one embodiment, one or more polymerization processesfor producing various polyolefins. (See for example U.S. patentapplication Ser. No. 09/615,376 filed Jul. 13, 2000, which is hereinfully incorporated by reference.)

Polymerization processes include solution, gas phase, slurry phase and ahigh pressure processes, or a combination thereof. Particularlypreferred is a gas phase or a slurry phase polymerization of one or moreolefin(s) at least one of which is ethylene or propylene. Thesepolymerization processes utilize a polymerization catalyst that caninclude any one or a combination of the molecular sieve catalystsdiscussed above, however, the preferred polymerization catalysts are theZiegler-Natta, Phillips-type, metallocene, metallocene-type and advancedpolymerization catalysts, and mixtures thereof.

In a preferred embodiment, the integrated process comprises a processfor polymerizing one or more olefin(s) in the presence of apolymerization catalyst system in a polymerization reactor to produceone or more polymer products, wherein the one or more olefin(s) havebeen made by converting an alcohol, particularly methanol, using amolecular sieve catalyst composition as described above. The preferredpolymerization process is a gas phase polymerization process and atleast one of the olefins(s) is either ethylene or propylene, andpreferably the polymerization catalyst system is a supported metallocenecatalyst system. In this embodiment, the supported metallocene catalystsystem comprises a support, a metallocene or metallocene-type compoundand an activator, preferably the activator is a non-coordinating anionor alumoxane, or combination thereof, and most preferably the activatoris alumoxane.

The polymers produced by the polymerization processes described aboveinclude linear low density polyethylene, elastomers, plastomers, highdensity polyethylene, low density polyethylene, polypropylene andpolypropylene copolymers. The propylene based polymers produced by thepolymerization processes include atactic polypropylene, isotacticpolypropylene, syndiotactic polypropylene, and propylene random, blockor impact copolymers.

EXAMPLES

In order to provide a better understanding of the present inventionincluding representative advantages thereof, the following Examples areoffered.

In the Examples, LEI is defined as the ratio of the lifetime of amolecular sieve catalyst composition containing an active metal oxide(s)compared to that of the same molecular sieve in the absence of a metaloxide, defined as having an LEI of 1. For the purpose of determiningLEI, lifetime is defined as the cumulative amount of oxygenateconverted, preferably into one or more olefin(s), per gram of molecularsieve, until the conversion rate drops to about 10% of its initialvalue. If the conversion has not fallen to 10% of its initial value bythe end of the experiment, lifetime is estimated by linear extrapolationbased on the rate of decrease in conversion over the last two datapoints in the experiment. For the purposes of determining the LEI forthe following Examples in a preferred oxygenate conversion process,methanol is converted to one or more olefin(s) at 475° C., 25 psig (172kPag) and a methanol weight hourly space velocity of 100 h−1.

“Prime Olefin” is the sum of the selectivity to ethylene and propylene.The ratio “C2=/C3=” is the ratio of the ethylene to propyleneselectivity weighted over the run. The “C3 Purity” is calculated bydividing the propylene selectivity by the sum of the propylene andpropane selectivities. The selectivities for methane, ethylene, ethane,propylene, propane, C4's and C5+'s are average selectivities weightedover the run. Note that the C5+'s consist only of C5's, C6's and C7's.The selectivity values do not sum to 100% in the Tables because theyhave been corrected for coke as is well known.

Example A

Preparation of Molecular Sieve

A silicoaluminophosphate molecular sieve, SAPO-34, designated as MSA,was crystallized in the presence of tetraethyl ammonium hydroxide (R1)and dipropylamine (R2) as the organic structure directing agents ortemplating agents. A mixture of the following mole ratio composition:0.2 SiO₂/Al₂O₃/P₂O₅/0.9 R1/1.5 R2 /50 H₂O.was prepared by initially mixing an amount of Condea Pural SB withdeionised water, to form a slurry. To this slurry was added an amount ofphosphoric acid (85%). These additions were made with stirring to form ahomogeneous mixture. To this homogeneous mixture Ludox AS40 (40% ofSiO2) was added, followed by the addition of R1 with mixing to form ahomogeneous mixture. To this homogeneous mixture R2 was added. Thishomogeneous mixture was then crystallized with agitation in a stainlesssteel autoclave by heating to 170° C. for 40 hours. This provided aslurry of the crystalline molecular sieve. The crystals were thenseparated from the mother liquor by filtration. The molecular sievecrystals were then mixed with a binder and matrix material and formedinto particles by spray drying.

Example B

Conversion Process

All catalytic or conversion data presented was obtained using amicroflow reactor consisting of a stainless steel reactor (¼ inch (0.64cm) outer diameter) located in a furnace to which vaporized methanol wasfed. The reactor was maintained at a temperature of 475° C. and apressure of 25 psig (172.4 kPag) The flow rate of the methanol was suchthat the flow rate of methanol on weight basis per gram of molecularsieve, also known as the weight hourly space velocity (WHSV) was 100h−1. Product gases exiting the reactor were collected and analyzed usinggas chromatography. The catalyst load in each experiment was 50 mg andthe reactor bed was diluted with quartz to minimize hot spots in thereactor. In particular, for the catalyst composition of the invention, aphysical mixture of the MSA molecular sieve of Example A and the activemetal oxide(s) was used. The total catalyst composition load remained 50mg, and the methanol flow rate was adjusted as the amount of molecularsieve in the reactor bed was reduced by the addition of the mixed metaloxide such that the methanol WHSV was 100 h−1 based on the amount ofmolecular sieve in the reactor bed.

Example 1

One thousand grams of ZrOCl2.8H2O was dissolved with stirring in 3.0liters of distilled water. Another solution containing 400 grams ofconcentrated NH4OH and 3.0 liters of distilled water was prepared. Bothsolutions were heated to 60° C. These two heated solutions were combinedat a rate of 50ml/min using nozzle mixing. The pH of the final compositewas adjusted to approximately 9 by the addition of concentrated ammoniumhydroxide. This slurry was then put in polypropylene bottles and placedin a steambox (100° C.) for 72 hours. The product formed was recoveredby filtration, washed with excess water, and dried overnight at 85° C. Aportion of this product was calcined to 700° C. in flowing air for 3hours to produce an active zirconium oxide material.

Example 2

Five hundred grams of ZrOCl2.8H2O and 84 grams of La(NO3)3.6H2O weredissolved with stirring in 3.0 liters of distilled water. Anothersolution containing 260 grams of concentrated NH4OH and 3.0 liters ofdistilled water was prepared. Both solutions were heated to 60° C. andthen combined at the rate of 50 ml/min using nozzle mixing to form thefinal mixture, a slurry. The pH of the final mixture was adjusted toapproximately 9 by the addition of concentrated ammonium hydroxide. Thisslurry was then put in a polypropylene bottle and placed in a steam box(100° C.) for 72 hours. The resulting product formed was recovered byfiltration, washed with excess water, and dried overnight at 85° C. Aportion of this product, was calcined to 700° C. in flowing air for 3hours to produce an active mixed metal oxide containing a nominal 10weight percent La (lanthanum) based on the final weight of the mixedmetal oxide.

Example 3

Fifty grams of ZrOCl2.8H2O were dissolved with stirring in 300 ml ofdistilled water. Another solution containing 4.2 grams of La(NO3)3.6H2Oand 300 ml of distill water was prepared. These two solutions werecombined with stirring to form a final mixture. The pH of the finalmixture, a slurry, was adjusted to approximately 9 by the addition ofconcentrated ammonium hydroxide (28.9 grams). This slurry was then putin a polypropylene bottle and placed in a steam box (100° C.) for 72hours. The resulting product formed was recovered by filtration, washedwith excess water, and dried overnight at 85° C. A portion of thisresulting product was calcined to 700° C. in flowing air for 3 hours toproduce an active mixed metal oxide containing a nominal 5 weightpercent La based on the final weight of the mixed metal oxide.

Example 4

Five hundred grams of ZrOCl2.8H2O and 70 grams of Y(NO3)3.5H2O weredissolved with stirring in 3.0 liters of distilled water. Anothersolution containing 260 grams of concentrated NH4OH and 3.0 liters ofdistilled water was prepared. Both solutions were heated to 60° C. andthen combined at the rate of 50 ml/min using nozzle mixing to form afinal mixture. The pH of the final mixture, a slurry, was adjusted toapproximately 9 by the addition of concentrated ammonium hydroxide. Thisslurry was then put in a polypropylene bottle and placed in a steam box(100° C.) for 72 hours. The resulting product formed was recovered byfiltration, washed with excess water, and dried overnight at 85° C. Aportion of the resulting product was calcined to 700° C. in flowing airfor 3 hours to produce an active mixed metal oxide containing a nominal10 weight percent Y (yttrium) based on the final weight of the mixedmetal oxide.

Example 5

Five hundred grams of ZrOCl2.8H2O and 56 grams of Ca(NO3)2.4H2O weredissolved with stirring in 3000 ml of distilled water. Another solutioncontaining 260 grams of NH4OH and 3000 ml of distilled water wasprepared. These two solutions were combined with stirring. The pH of thefinal composite was adjusted to approximately 9 by the addition ofconcentrated ammonium hydroxide (160 grams). This slurry was then put inpolypropylene bottles and placed in a steambox (100° C.) for 72 hours.The resulting product formed was recovered by filtration, washed withexcess water, and dried overnight at 85° C. A portion of this productwas calcined to 700° C. in flowing air for 3 hours to produce an activemixed metal oxide containing a nominal 5 weight percent Ca (calcium)based on the final weight of the mixed metal oxide.

Example 6

Seventy grams of TiOSO₄·xH₂SO₄·xH₂O (x=1) were dissolved with stirringin 400 ml of distilled water. Another solution containing 12.8 grams ofCeSO₄ and 300 ml of distilled water was prepared. These two solutionswere combined with stirring. The pH of the final composite was adjustedto approximately 8 by the addition of concentrated ammonium hydroxide(64.3 grams). This slurry was then put in polypropylene bottles andplaced in a steambox (100° C.) for 72 hours. The product formed wasrecovered by filtration, washed with excess water, and dried overnightat 85° C. A portion of this product was calcined to 700° C. in flowingair for 3 hours to produce an active mixed metal oxide containing anominal 5 weight percent Ce based on the final weight of the mixed metaloxide.

Example 7

Five grams of HfOCl₂·xH₂O was dissolved with stirring in 100 ml ofdistilled water. The pH of the final composite was adjusted toapproximately 9 by the addition of concentrated ammonium hydroxide (4.5grams). This slurry was then put in a polypropylene bottle and placed ina steambox (100° C.) for 72 hours. The product formed was recovered byfiltration, washed with excess water, and dried overnight at 85° C. Aportion of this catalyst was calcined to 700° C. in flowing air for 3hours to produce an active hafnium oxide.

Example 8

Five grams of HfOCl₂·xH₂O and 0.62 grams of La(NO₃)₃·6H₂O were dissolvedwith stirring in 100 ml of distilled water. The pH of the finalcomposite was adjusted to approximately 9 by the addition ofconcentrated ammonium hydroxide (3.5 grams). This slurry was then put ina polypropylene bottle and placed in a steambox (100° C.) for 72 hours.The product formed was recovered by filtration, washed with excesswater, and dried overnight at 85° C. A portion of this catalyst wascalcined to 700° C. in flowing air for 3 hours to produce an activemixed metal oxide containing a nominal 5 weight % La based on the finalweight of the mixed metal oxide.

Example 9

The carbon dioxide uptake of the oxides of Examples 1 through 8 weremeasured using a Mettler TGA/SDTA 851 thermogravimetric analysis systemunder ambient pressure. The metal oxide samples were first dehydrated inflowing air to about 500° C. for one hour after which the uptake ofcarbon dioxide was measured at 100° C. The surface area of the sampleswere measured in accordance with the method of Brunauer, Emmett, andTeller (BET) to provide the carbon dioxide uptake in terms of mg carbondioxide/m² of the metal oxide presented in Table 1.

TABLE 1 Catalyst Dry Surface Area CO₂ Uptake Example Weight (mg) mg ofCO₂ (m²/g) (mg of CO₂/m²) 1 76 0.0980 29 0.045 2 115 0.7781 80 0.085 373 0.4243 89 0.065 4 97 0.3808 100 0.039 5 78 0.5399 85 0.081 6 430.1035 50 0.048 7 158 0.3704 25 0.094 8 164 0.7359 60 0.075

Example 10 (Comparative)

The performance of the control, the molecular sieve of Example A, MSA,using a 50 mg load in the reactor and under the conditions discussedabove in Example B is reported in Tables 2 and 3.

Example 11

In this Example, the catalyst composition consisted of 40 mg MSA ofExample A and 10 mg of the active zirconium oxide of Example 1. Thecatalyst composition and active mixed metal oxide were well mixed, andthen diluted with quartz to form the reactor bed. The results of testingthis catalyst composition in the process of Example B are shown inTables 2 and 3. The results indicate that the addition of the activezirconium oxide to the catalyst bed increased the lifetime of themolecular sieve composition significantly, and decreased the amounts ofundesired ethane and propane.

Example 12

In this Example, the catalyst composition consisted of 40 mg MSA ofExample A and 10 mg of the active mixed metal oxide containing 10 weightpercent La, described in Example 2. The catalyst composition and activemixed metal oxide were well mixed, and then diluted with quartz to formthe reactor bed. The results of testing this catalyst composition in theprocess of Example B are shown in Tables 2 and 3. The data in Tables 2and 3 illustrate that by constituting 20% of the catalyst compositionload with the active mixed metal oxide containing 10 weight percent La,the lifetime of the molecular sieve doubled, as indicated by its LEIvalue of 2. In addition, there was a net gain of 1.7% in prime olefinson an absolute basis, with most of this gain being due to an increase inpropylene of 2.76%, offsetting a small decrease in ethylene of 1.07%.Selectivity to ethane decreased by 39% and selectivity to propanedecreased by 37% suggesting that hydrogen transfer reactions have beensignificantly reduced.

Example 13

In this Example, the catalyst consisted of 30 mg MSA of Example A and 20mg of the active mixed metal oxide containing 10 weight percent La, asdescribed in Example 2. The catalyst composition and active mixed metaloxide were well mixed, and then diluted with quartz to form the reactorbed. The results of testing this catalyst composition in the process ofExample B are shown in Tables 2 and 3. The data of Tables 2 and 3illustrate that by constituting 40% of the catalyst composition loadcontaining 10 weight percent La, the lifetime of the SAPO-34 catalystcomposition increased by 440%. Trends in selectivity for this catalystloading are similar to those seen in Example 8.

Example 14

In this Example, the catalyst composition consisted of 40 mg MSA fromExample A and 10 mg of the active mixed metal oxide containing 10 weightpercent Y, as described in Example 4. The catalyst composition andactive mixed metal oxide were well mixed, and then diluted with quartzto form the reactor bed. The results of testing this catalystcomposition in the process of Example B are shown in Tables 2 and 3. Thesubstitution of yttrium for lanthanum has the effect of increasing theLEI even further. However, the improvements in selectivity are not asdramatic as seen with the lanthanum, with the gain in prime olefin being1.2% on an absolute basis.

Example 15

In this Example, the catalyst consisted of 40 mg MSA of Example A and 10mg of the active mixed metal oxide containing 5 weight percent La, asdescribed in Example 3. The catalyst composition and active mixed metaloxide were well mixed, and then diluted with quartz to form the reactorbed. The results of testing this catalyst composition in the process ofExample B are shown in Tables 2 and 3. It will be seen that the activemixed metal oxide containing 5 weight percent lanthanum oxide seems tohave a much stronger effect in increasing the LEI than the active mixedmetal oxide of Example 8 containing 10 weight percent La.

Example 16

In this Example 16, the catalyst consisted of 40 mg MSA of Example A and10 mg of an active mixed metal oxide containing 5 weight percent Ca, asdescribed in Example 5. The catalyst composition and active mixed metaloxide were well mixed, and then diluted with quartz to form the reactorbed. The results of this experiment in the reactor and conditionsdiscussed above in Example B are shown in Tables 2 and 3. The activemixed metal oxide containing 5 weight percent calcium oxide hasincreased the lifetime of the molecular sieve composition by 223%.

Example 17 (Comparative)

In this Comparative Example, the catalyst composition consisted of 40 mgMSA of Example A and 10 mg of an amorphous silica/alumina, an inactivemixed metal oxide. The molecular sieve catalyst composition and theinactive mixed metal oxide catalysts were well mixed, and then dilutedwith quartz to form the reactor bed. The results of testing thiscatalyst composition in the process of Example B are also shown inTables 2 and 3. This Comparative Example 17 illustrates a reduction inLEI to a value less than 1.0 when an inactive mixed metal oxide isutilized as compared to Example 11 of the invention. In addition, thereis a loss of 1.07% in prime olefin selectivity, and no significantreduction in ethane and propane production.

Example 18

In this Example, the catalyst composition consisted of 40 mg MSA fromExample A and 10 mg an active mixed metal oxide containing Ce andtitania, as described in Example 6. The catalyst composition and activemixed metal oxide were well mixed, and then diluted with quartz to formthe reactor bed. The results of testing this catalyst composition in theprocess of Example B are shown in Tables 2 and 3. The presence of theactive mixed metal oxide increased the lifetime of the molecular sievecomposition by 134%.

Example 19

In this Example, the catalyst composition consisted of 40 mg MSA ofExample A and 10 mg of the active hafnium metal oxide described inExample 7. The catalyst composition and active metal oxide were wellmixed, and then diluted with quartz to form the reactor bed. The resultsof testing this catalyst composition in the process of Example B areshown in Tables 2 and 3. The data in Tables 2 and 3 illustrate that byconstituting 20% of the catalyst composition load with the activehafnium metal oxide, the lifetime of the molecular sieve has increasedby 126%. Selectivity to ethane decreased by 40% and selectivity topropane decreased by 46% suggesting that hydrogen transfer reactionshave been significantly reduced.

Example 20

In this Example, the catalyst composition consisted of 40 mg MSA ofExample A and 10 mg of the active mixed metal oxide containing 5 weightpercent La, described in Example 8. The catalyst composition and activemixed metal oxide were well mixed, and then diluted with quartz to formthe reactor bed. The results of testing this catalyst composition in theprocess of Example B are shown in Tables 2 and 3. The data in Tables 2and 3 illustrate that by constituting 20% of the catalyst compositionload with the active mixed metal oxide containing 5 weight percent La,the lifetime of the molecular sieve has increased by 150%. Selectivityto ethane decreased by 51% and selectivity to propane decreased by 51%suggesting that hydrogen transfer reactions have been significantlyreduced.

TABLE 2 Reactor Bed Prime C₃ Exam- Composition Olefin C₂ ^(=/) Purityple (wt%) LEI (%) C₃ ⁼ (%) 10 100% MSA 1 74.65 0.92 92.7 (Comp) 11 80%MSA / 2.64 74.79 0.82 96.1 20% ZrO₂ 12 80% MSA / 2.03 76.34 0.84 95.620% of 10% La/ZrO₂ 13 60% MSA / 5.41 75.50 0.85 94.6 40% of 10% La/ZrO₂14 80% MSA / 2.79 75.81 0.85 94.9 20% of 10% Y/ZrO₂ 15 80% MSA / 4.8575.84 0.84 94.8 20% of 5% La/ZrO₂ 16 80% MSA / 3.23 73.85 0.79 96.7 20%of 5% Ca/ZrO₂ 17 80% MSA / 0.79 73.58 0.93 93.3 (Comp) 20% of SiO₂/Al₂O₃ 18 80% MSA / 2.34 65.65 0.87 95.1 20% of Ce/ TiO₂ 19 80% MSA /2.26 72.98 0.71 96.2 20% of HfO₂ 20 80% MSA / 2.50 72.75 0.76 96.5 20%of 5% La/HfO₂

TABLE 3 Exam- Reactor Product Selectivities (%) ple Bed (wt %) CH₄ C₂ ⁼C₂ ^(o) C₃ ⁼ C₃ ^(o) C₄'s C₅+ 10 100% MSA 1.51 35.82 0.95 38.83 3.0514.50 2.12 (Comp) 11 80% MSA / 1.50 33.74 0.53 41.05 1.68 14.79 3.31 20%ZrO₂ 12 80% MSA / 1.31 34.75 0.58 41.59 1.93 14.96 2.46 20% of 10%La/ZrO₂ 13 60% MSA / 1.47 34.75 0.66 40.75 2.32 14.76 2.52 40% of 10%La/ZrO₂ 14 80% MSA / 1.32 34.92 0.66 40.88 2.20 14.41 3.07 20% of 10%Y/ZrO₂ 15 80% MSA / 1.26 34.59 0.64 41.25 2.28 14.96 2.52 20% of 5%La/ZrO₂ 16 80% MSA / 1.50 32.65 0.42 41.20 1.43 14.84 5.34 20% of 5%Ca/ZrO₂ 17 80% MSA / 2.17 35.46 0.89 38.12 2.72 14.21 2.65 (Comp) 20% ofSiO₂/Al₂O₃ 18 80% MSA / 6.79 30.57 0.75 35.09 1.80 12.72 3.97 20% of Ce/TiO₂ 19 80% MSA / 1.98 31.62 0.52 41.36 1.65 14.64 4.93 20% of HfO₂ 2080% MSA / 1.98 31.58 0.47 41.18 1.49 14.53 5.52 20% of 5% La/HfO₂

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For example, it is contemplated that themolecular sieve compositions described herein are useful as absorbents,adsorbents, gas separators, detergents, water purifiers, and for othervarious uses such as agriculture and horticulture. It is within thescope of this invention to add one or more active metal oxide(s) to thesynthesis mixture for making a molecular sieve as described above. Forthis reason, then, reference should be made solely to the appendedclaims for purposes of determining the true scope of the presentinvention.

1. A catalyst composition comprising a molecular sieve and at least one oxide of a metal selected from Group 4 of the Periodic Table of Elements, wherein said metal oxide has an uptake of carbon dioxide at 100° C. of at least 0.03 mg/m² of the metal oxide.
 2. The catalyst composition of claim 1 wherein said metal oxide has an uptake of carbon dioxide at 100° C. of at least 0.035 mg/m² of the metal oxide.
 3. The catalyst composition of claim 1 wherein said metal oxide has an uptake of carbon dioxide at 100° C. of less than 10 mg/m² of the metal oxide.
 4. The catalyst composition of claim 1 wherein said metal oxide has an uptake of carbon dioxide at 100° C. of less than 5 mg/m² of the metal oxide.
 5. The catalyst composition of claim 1 and also including at least one of a binder and a matrix material different from said metal oxide.
 6. The catalyst composition of claim 1 wherein said metal oxide has a surface area greater than 10 m²/g.
 7. The catalyst composition of claim 1 and also including a binder and a matrix material each being different from one another and from said metal oxide.
 8. The catalyst composition of claim 7 wherein the binder is an alumina sol and the matrix material is a clay.
 9. The catalyst composition of claim 1 wherein said metal oxide is selected from zirconium oxide and hafnium oxide.
 10. The catalyst composition of claim 1 and also including an oxide of a metal selected from Group 2 and Group 3 of the Periodic Table of Elements.
 11. The catalyst composition of claim 10 wherein the Group 4 metal oxide comprises zirconium oxide and the Group 2 and/or Group 3 metal oxide comprises one or more oxides selected from the group consisting of calcium oxide, barium oxide, lanthanum oxide, yttrium oxide and scandium oxide.
 12. The catalyst composition of claim 1 wherein the molecular sieve comprises a framework inciuding at least two tetrahedral units selected from [SiO₄], [AlO₄] and [P0 ₄] units.
 13. The catalyst composition of claim 12 wherein the molecular sieve comprises a silicoaluminophosphate.
 14. The catalyst composition of claim 12 wherein the molecular sieve comprises a CHA framework-type molecular sieve.
 15. The catalyst composition of claim 14 wherein the molecular sieve further comprises an AEI framework-type molecular sieve.
 16. The catalyst composition of claim 1 wherein the weight ratio of the molecular sieve to metal oxide is in the range of from 5 percent to 800 percent.
 17. A molecular sieve catalyst composition comprising an active Group 4 metal oxide and a Group 2 and/or a Group 3 metal oxide, a binder, a matrix material, and a silicoaluminophosphate molecular sieve.
 18. A method for making a catalyst composition, the method comprising physically mixing first particles comprising a molecular sieve with second particles comprising a Group 4 metal oxide having an uptake of carbon dioxide at 100° C. of at least 0.03 mg/m² of the metal oxide particles.
 19. The method of claim 18 wherein said second particles have a surface area greater than 10 m²/g.
 20. The method of claim 18 wherein said second particles have a surface area greater than 15 m²/g.
 21. The method of claim 18 wherein said first particles comprise a silicoaluminophosphate molecular sieve and/or an aluminophosphate molecular sieve.
 22. The method of claim 18 wherein at least one said first and said second particles also include at least one of a binder and a matrix material.
 23. The method of claim 18 wherein said first particles comprise a silicoaluminophosphate molecular sieve, a binder including an alumina sol and a matrix material including a clay.
 24. The method of claim 18 wherein said second particles also comprise a Group 2 and/or Group 3 metal oxide.
 25. The method of claim 18 wherein said second particles comprise zirconium oxide and at least one of calcium oxide, barium oxide, lanthanum oxide, yttrium oxide and scandium oxide.
 26. A method of making a catalyst composition, the method comprising: (i) synthesizing a molecular sieve from a reaction mixture comprising at least one templating agent and at least two of a silicon source, a phosphorus source and an aluminum source; and (ii) recovering the molecular sieve synthesized in (i); (iii) forming a hydrated precursor of a Group 4 metal oxide by precipitation from a solution containing a source of Group 4 metal ions; (iv) recovering the hydrated precursor formed in (iii); (v) calcining the hydrated precursor recovered (iv) to form a calcined Group 4 metal oxide that has an uptake of carbon dioxide at 100° C. of at least 0.03 mg/m² of the metal oxide; and (vi) physically mixing the molecular sieve recovered in (i) and the calcined metal oxide produced in (v).
 27. The method of claim 26 wherein the molecular sieve and/or the Group 4 metal oxide is combined with a binder and/or a matrix material prior to (vi).
 28. The method of claim 26 wherein the weight ratio of the molecular sieve to the calcined metal oxide is in the range of from 30 percent to 400 percent.
 29. The method of claim 26 wherein the calcined metal oxide has a surface area greater than 10 m²/g.
 30. The method of claim 26 wherein the molecular sieve is spray dried with a matrix material and a binder prior to (vi).
 31. The method of claim 30 wherein the molecular sieve is a silicoaluminophosphate, the binder is an alumina sol and the matrix material is a clay.
 32. The method of claim 26 wherein a mixed metal oxide is produced in (iii) by precipitation from at least one solution containing a Group 4 metal oxide precursor and at least one of a Group 2 metal oxide precursor and a Group 3 metal oxide precursor.
 33. The method of claim 26 wherein said precipitation is conducted at a pH above
 7. 34. The method of claim 26 wherein (iii) also includes hydrothermally treating the precipitate at a temperature of at least 80° C. for up to 10 days.
 35. The method of claim 26 wherein (v) is conducted at a temperature in the range of from about 400° C. to about 900° C. 